Mechanical seal assembly and method of operation



April 5, 1960 E. s. HARRISON 2,931,631

MECHANICAL SEAL ASSEMBLY AND METHOD oF OPERATION Filed Oct. 28, k1954 4Sheets-Sheet 1 1N VEN TOR. EDM/AED 5. #AEE/60N ATTORNEYS April 5, 1960E. s. HARRISON 2,931,631

MECHANICAL SEAL ASSEMBLY AND METHOD OF OPERATION Filed om. 2a, 1954 4sheets-sheet 2 INVENTOR. Dn/ABD s, HABE/50N BY P/CHE); WA rr's, @D ro/ve M NENNY NAI A TTOENEYS April 5, 1960 E. s. HARRISON 2,931,631

MECHANICAL SEAL ASSEMBLY AND METHOD 0E OPERATION Filed oct. 28, 1954 4sheets-sheet s INVENTOR. DMLPD 5. HAze/SQN April 5, 1960 E. s. HARRISON2,931,631

MECHANICAL SEAL ASSEMBLY AND METHOD oF OPERATION Filed Oct. 28, 1954 4Sheets-Sheet 4 INVENTOR. D14/AED S. HABE/30N BY E/CHE); WA 771s, kaer eMWENNY MECHANICAL SEAL ASSEMBLY AND METHOD QF OPERATIQN Edward S.Harrison, La Grange, Ohio, assigner to rEhe liYfarller Co., Rochester,vN.Y. a corporation of New or A Y.

Application October 28, 1954, Serial No. 465,390 s Clarins. (ci.257-7305) The present invention relates to the heat exchange art and ismore particularly concerned with unique apparatus for use in controllingrthe temperatureof a liquid, for example a liquid in a mechanical seal.l

In general, in the operation of any mechanical seal, -it is necessary tomaintain a uid at the seal faces. For high-pressurel andhigh-temperature operation of any reactor .or autoclave with Va doublemechanical seal assembly, it is generally necessaryto maintain the sealchamber duid at a pressure substantially'above the reactor pressurelbutwata temperature not in excess of about '2502 F. In the past, it hasbeen the general practice, in meeting these requirements, to provide acirculating `liquid with a reseryoirfand a pump being used to keep thesealing 'liquid moving through the seal chamber at a suicie'nt iratethat .the temperature of the liquid `will not exceedva predeterminedlimit regardless of reactor 4temperature 4and `the temperature of theadjacent and surrounding elements of the seal assembly. This .practice,however, is not satisfactory from the standpoint of the initialequipment cost Vand the costs of operation and maintenance. In(addition, this ,type of equipment is not flexible enough 4foradaptation generally and accordingly custom building of the yunits hasbecome general practice. l

Inaccordance with our present invention, the foregoing diiculties andshortcomings of the prior art have been completely 4eliminated ormaterially diminished and additional important advantages are obtained.T-hus,`the pump unit, `which was always heretofore essential, is notvrequired :in `the apparatus and method `of `this invention.

Consequently, the ,cost of the .pump and the attending cost l,ofinstallation; including wiring of Vthe pump motor and plumbing of thepump system, have herebybeen eliminated. Furthermore, the variousapparatus and as'- se-mblies of .this im/ention can be `used withoutspecial adaptation or modification in a wide variety'of mechan- -icalseal systems. AStill further, `there is an almost unlimited .variety ofuids which can be usedto effect seal- -ing in accordance `with .thepresent method and apparatus and no consideration need be given v.theproblem of selecting a particular ,fluid Aon the basis of .pumprequirements or ,similar problems. In addition, because there are nomoving parts inthe apparatus of this invention .for causing the ',uid tocirculate in the system and because this v apparatus depends .upon .nooutside power source ,for .maintaining sealpressure, there is nolikeli-l hood of the Idanger of failure in use. Also, there is nopossibility, in accordance with this invention, of a y'large amount ofsealing fluid Yentering a reactor, the amount .of uid used .being,limited lto .a relatively ,small quantity .suicient merely `to.producethe circulating effects essential to proper sealing.

i' arent Our .present invention is, toa large degree, predicated ,uponour discovery that under certain circumstances, a .fluid .suitablelforiuse ,in mechanical seal assemblies may be caused .to ,circulate ina natural way and this circulation .continuous yand substantiallyuniform ,over

section, of an assemblyv including a reactor vessel equipped Awithanagitator and a rotary seal;

Patented Apr, 5, i960 videthe temperature control over the uidnecessary` to assure the sealing effects desired. This invention is alsobased upon our discovery that such circulation of the seal uid will notbe signiiicantly effected adversely by changes in pressure upon thefluid.

Briefly, the method of this invention comprises the steps of'circulatiuga iiuid through a circuit which includes a seal housing and a fluidreservoir and establishing and maintaining a pressure on uid in thereservoir substantially above the pressure to besealed and 'therebyestablishing and maintaining substantially the same elevated pressureupon fluid within the seal housing throughout the period of operation ofthe seal.

In accordance with a preferred practice of this invention, the fluid iscirculated through a circuit in a closed system. However, i-t will beunderstood that the system may be open to the atmosphere under certaincircumstancesv throughout lthe period of operation. lf, for eX- amp-le,the reactor is being operated under a partial vacuum, the method andapparatus of this invention will be effective to establish and maintainthe desired mechanical seal although operating under substantiallynormal atmospheric pressure. ln any event, however, in the preferredpractice of this invention the pressure to which the sealing liquid issubject throughout the sealing period will be between about ten poundsper square inch and `about l0() pounds per square inch greater than thepressure of the system to be sealed. Generally, for practicalV purposes,a pressure difference of about 25 pounds per square inch will be foundsatisfactory.

When the present method is carried out in a closed system, the object inaccordance with our preference, is primarily to impose an elevatedpressure upon the sealing fluid throughout the system and particularlyat Vthe seal faces. This may be accomplished by substantiallydiminishing the volume of the system While maintaining substantiallyconstant the amount of fluid in the system. Alternatively, this resultis obtained by substantially increasing the amount of fluid in thesystem while maintaining the system volume substantially constant. Inany event, by the nature of the present method and apparatus, it will beunderstood that whatever method is used for elevating pressure of thefluid, an increase of pressure upon any portion of the uid will beuniformly distributed `throughout the fluid and it is thus possible toregulate over wide ranges and within narrow limits, .the pressure of theuid at the kcritical seal face locations by means operating directlyonly at ther'emotest end of the apparatus from that location.

Ordinarily, the uidernployed for actual sealing will be a' liquid, but aliquid and gas will be contained in `the reservoir of the system, whileonly liquid will be present in the seal housing. The gas may be acted ondirectly or indirectly for the purpose of adjusting and maintainingpressure of the iiuid. Also, the gas may serve as a cushion againstshocksin the system and thus operate as a safety device. Still further,the gas may be selected for specific chemical effects which it maylexert upon the liquid for purposes of corrosion resistance such asinhibition of autocatalytic decomposition. v'On yconsideration ofthefollowing detailed description, read in conjunction with the followingdrawings, accomfpanying and forming a part of the specification, thoseskilled in the art will gain va better understanding of the method andapparatus aspects ofv our present invention andthe important advantagesof which it holds over the priorart.

In the drawings:

Fig. 1 is a fragmentary, elevational view, partly in asian Fig. 2 is anelevational view, partly in section, of an assembly including the rotaryseal of Fig. l and an aplfnaratus embodying the present invention in apreferred orm;

Fig. 3 is a view similar to Fig. 2 showing another form of apparatus ofthis invention;

Fig. 4 is a fragmentary, enlarged sectional view of a portion of thepressure-regulating sub-assembly of the Fig. 3 apparatus; and,

Fig. 5 is an elevational view, partly in section, of still another formof apparatus of this invention.

As indicated in the drawings, apparatus of this invention generallycomprises a vessel to contain a liuid, an inlet port in the vessel, anoutlet port in alower portion of the vessel, and means consistingessentially of tubes for separately connecting the inlet and outletports to a mechanical seal housing for free circulation of the fluidbetween the vessel and the housing.

The apparatus of this invention illustrated in Fig. 1, is applied to andused with equipment commonly employed in the chemical industry includingan autoclavetype reactor vessel V which has a flanged nozzle formed atits top to receive an agitator shaft 12. Nozzle 10 and shaft 12 aresealed in accordance with this invention for maintenance of any desiredpressure within the reactor by means of a seal assembly S and theassociated equipment shown in Figs. 2, 3 or 5.

Assembly S comprises an outer shell or housing 15 in the form of agenerally cylindrical body open at its ends to receive shaft 12 andprovided with anges 16 and 17 having a plurality of transverse openingsfor registry with apertures in a drive bearing 19 and an annular ring20. By means of a plurality of bolts 21 and 22, housing 15 is securelyfastened to bearing 19 and vessel V. An annular ceramic seat 27 disposedin housing 15 bears upon a sealing ring assembly 29 which is deformed bypressure exerted in drawing up ring to produce a gas-tight seal betweenassembly S and vessel V.

A reduced diameter portion 31 of bearing-19 extends downwardly withinthe upper end of housing 15 closing the housing at its upper end. Thus,an annular chamber 33 is defined within the shell of assembly S,surrounding shaft 12 and extending from adjacent to the upper end of thehousing to adjacent its lower end. To provide fluid coolant for parts tobe disposed within chamber 33, an inlet passageway 35 is formed in aportion of housing 15 adjacent to liange 17 and an outlet passageway 36is formed in upper flange 16. For convenience in making conduitconnections to these passageways, screw threads are formed in theirexternal openings.

The lower end of chamber 33 is sealed against escape of fluid intovessel V and vessel V is likewise sealed against loss of liuid aroundshaft 12 by means of an annular, wedge-shaped Teflon body 40 and acarbon ring 41 having a tapered end for engagement with wedge 40 whichis held in place against an abutment wall 42 formed on the agitatorshaft and extending radially outwardly therefrom. A spring assemblyincluding a compression spring 45 in a metal cage 46 carried by shaft 12constantly resiliently urges ring 41 into firm engagement with wedge 40,holding the wedge in sealing position against abutment 42.

The upper end of seal chamber 33 is sealed by similar means including awedge body 48, a carbon ring 49, an abutment wall 51 and a springassembly. Ring 49 is of slightly different physical form in order toprovide firm anchorage against a stationary annular seat 53 situatedwithin the lower end of the drive bearing. CarbonV ring 41 derives itssupport from ceramic seat 27 bearing against the upper surface portionthereof.

The apparatus of this invention illustrated in Fig. 2 in operativerelation to seal housing S comprises an elongated, generally cylindricalor tubular vessel 55, the lower end of which is closed by means of ametal plate or disc 56 which is welded to the vessel. The upper 'end ofthe cylinder has welded Huid-tightly secured to it a dome-like body 58of enlarged inside diameter which is sealed except for communicationwith the cylinder. A standpipe 59 is disposed within the cylinderextending upwardly through an opening in plate 56 to a point well abovethe mid-section of vessel 55. The upper end of standpipe 59 is open andwhile it is fluid-tightly secured in place to the bottom plate, pipe 59extends therethrough and opens into a coupling 61 which in turn leadsinto a tube 62, an elbow 64 and another tube 65, which communicates withseal chamber 33 through outlet passageway 36. A coil 70 of tubing ofsubstantially reduced diameter is disposed within vessel 55 aroundstandpipe 59 from which it is spaced. Coil 70 has an upper end Vportion71 which extends outwardly to an opening provided for that purpose inthe upper end portion of vessel 55 and has a lower end portion 72 whichextends downwardly through an opening in plate 56 likewise provided forthis purpose. Where it enters the vessel, the coil is gas-tightlysecured to the vessel to prevent leakage during the operation of theapparatus of this invention.

In the side wall of the cylindrical vessel near the lower end thereof,an outlet port 75 is provided to permit ow of uid from the vessel toseal chamber 33 by means of a conduit assembly 77 fluid-tightlyconnected to the vessel and to seal assembly S in which it communicateswith passageway 35.

In the upper portion of the vessel, an inlet opening 80 is provided anda conduit 81 is connected to the vessel wall Huid-tightly incommunication with this opening for filling the vessel with heatexchange fiuid to be used in maintaining the desired temperature inchamber 33 and in maintaining the desired seal throughout the period ofuse of the reactor vessel. A valve 83 is provided to close fluid tightlythe inlet conduit during operation of this apparatus.

Above opening 80, an aperture 85 is formed in the vessel wall and aneedle valve 86 and a pressure gauge 87 are connected to the vessel bymeans of a pipe assembly 89 fluid-tightly welded to the vessel forcommunication with the vessel chamber to enable detection and regula.-tion of fluid pressure in the vessels.

For the purpose of regulating pressure in the vessel chamber and foradding make-up amounts of heat exchange liquid, an Alemite gun 90 isdisposed adjacent to the vessel and held in position by means ofsupporting bars 92 welded to the vessel and to the gun cylinder. A tube94 of reduced diameter connects gun 90 to vessel 55 through an openingprovided for this purpose near the bottom of the vessel. Manipulation ofgun 90 in the usual manner results in the introduction of heat exchangeliquid under pressure into vessel 55.

In operation of the apparatus of Fig. 2, a suitable heat Vexchangeliquid is run into the vessel through valve 83,

pipe 81 and opening 80, needle valve 86 being open to permit free liowof liquid to approximately the desired level in the vessel. The needlevalve and inlet control valve 83are closed when the desired amount ofliquid has been charged into the system and gun 90 is operated to addstill more liquid to the vessel, thereby increasing the gas pressure inthe upper part of vessel 55 and dome 58 to a desired level, aslindicated by pressure gauge 87.

`Before reactor vessel V is brought up to operating temperature, thesupply system serving the cooling coil 70 is started so that ow ofcoolant through the coil is begun in time to assure the desired heatexchangewith vessel liquid contents to produce the circulating flowcharacteristic of the novel method of this invention. With the systembrought to this stage, no minor attentionis rcquired of the operatorduring the period of reactor operation and sealing of the reactor aroundthe agitator shaft is assured throughout the period of operation,assuming the selection of a heat exchange liquid meeting therequirements of the service. In other words, no moving parts, such aspumps or the like, are required to maintain the desired liquid sealing'pressure in the sealing chamber" orf tonantaii' tlie desired` tempertein the liquid effecting this seal throughout" the period of operation ofthe reactor dueto the vc'vontinu, Substantial circulation resulting fromthe thermal"differentialv between liquid entering passageway 35anddiquid' leavingcliamber 33 through passageway 36;v j l j Withreferenceto Figs. 3- and 4',:thealternative."l form of apparatus ofthis'invention therein; illustratedl cornprises an elongatedcylindricalve'ss'el 98 similar to; vessel 55, having an endV plate 99Vclosing' its lower end.` An inlet opening is provided in said plate forreceipt of; a standpipe 101 which extends upvi/arcl'ly'L to near thetopof the vessel. An outlet opening 1035 is' provided in the side wall ofthe vessel adjacentV toitslower end aridfby means of conduitassemblies^104^and-1`tl5, standpipeiltll and outlet opening 103 areciiected to passages 36 and 35, respectively, for' circulatioii ofsealing liquida between vessel 98 and seal assembly Siin the mannergenerally described above irirefeieiice to Fig. 2.

The upperl end portion of thevessel' 98 is'clsedf by means of a metalplug 110 which is'welded ti'- the: top of the vessel andprovidedwith'aceritral bre 111 to receive a plunger or piston 113 formaintaining predetermined pressure in vessel 98. A bracket 11Scomprising a metal bar is welded to the outer side of plug 110 andextends upwardly from the plug to support pivotally a lever 116 which isconnected to an upward extension of piston 113. The free end of lever116 is maintained in place during operation of the apparatus of thisinvention by means of a Weight 117 which is connected by means of achain 11S to the lever through an opening provided for the purpose inthe said free end of the lever. formed on the upper end of the plug, anupstanding portion of predetermined length such that lever 116, when inthe down position, is supported against weight 117 in a substantiallyhorizontal position with piston r113 in its advanced or down position.

A cooling coil 120 of reduced diameter tubing, like coil 70 of Fig. 2,is disposed within vessel 93 surrounding standpipe 161 and spacedtherefrom. Lower end 121 of the coil is run out through bottom wall 99of the cylinder to which it is fluid-tightly connected for communicationwith a supply of cooling water (not shown). Upper end 122 ofcoil 120 isrun out through the top Diametrically opposed to bracket 115, there isof the assembly through an opening provided in plug and it is similarlysecured thereto gas-tightly to prevent ioss of pressure in the Vvesselduring operation. This coil outlet line communicates suitably with adrain (not shown).

An aperture 125 is located in the upper portion of the vessel forconnection of apressure gauge V127 to the vessel interior through a pipe128 duid-tightly attached to the outside of the said vessel.

Alemite-type grease gun 130 is supportedby cylinder 98 in a positionadjacent thereto by means of suspension bars 131 which are welded to thevessel and the cylindrical portion of the gun. Gun 1.3i) communicateswith vessel 98 through tube 133 and an opening 134 in the lower portionof the vessel. The gun also communicates .with the vessel through a tube135 and a passageway 136 formed in plug 110 above the mid-section of theplug.

The apparatus illustrated in Figs. 3 and 4 is used to establish andmaintain the desired sealing pressure and the desired temperature in thesealing chamber by irst charging into vessel 98, the desired amount ofsuitable sealing liquid. Filling of the vessel is accomplished byremoving piston 113 from plug 110 and charging the liquid into thevessel through plug bore 111. When the level of the liquid in the vesselreaches the desired point, piston 113 is replaced in its bore and weight117 is connected to lever 116 so that the piston is moved into Vitsadvanced position. Gun 1311 is then operated to bring the pressure invessel 98 to the desired level as indicated origaugel 127 i andv flowofcooling- Watev thrciughcoil 120 isv begun. Circulation` of theYsealing liquid` through" seal chamber 33 and vessel 98V and thelinescbnnecting thm begins as soon astlie temperature differentialbetweenthe liquid in inletl and" outlet passageways 35 and 36is'suificient to produce thisl effect. This circulationwill coni tinue,as those skilledin' the art will understand, throughout the operatingperiod' so long as i't is necessary to elec'tcooling withinY the sealchamber.

The assembly of Figs. 3 and 4 has a special feature, in that there is asafety release'built'into the assembly i so that pressure inthe vesselcannot exceeda certain pre- -determined limit which is sufficient tocause motion of the piston` away from its advanced position sufiicientlytofl uncover port 136; Accordingly, the pistonand lever 116 and weight117 may be desired with respect to each other and to the pressure"vessel and' with regard t'o the temperatures and vapor pressures to be`carried irivessel '98' so'that emergency release may be automatically`accomplished to insure against dain'age resulting from exfces'sivepressure developing anywhere in this vessel-sealing assembly system.

The apparatus shown in Fig. 5 comprises a cylindrical vessel 140 whichis closed at its lower end by a plate 141 provided with a centralopening to receive a standpipe 142 generally as described above. Anoutlet opening 144 is provided near the lower end of the vessel and asin the foregoing embodiments of thisY invention, the inlet and outletopenings are served by suitable conduit means 147 and 148 for connectionto seal assembly S.

A jacket 150 is provided on vessel 140 forcooling uid to exert a heatexchange eiiect on the liquid of the seal system contained in the saidvessel and in standpipe 142. Cooling tluid is introduced into jacket 150through inlet port 151 and is discharged through outlet port 152.

It will be understood that this Fig. 5 device is not intended to beoperated under superatmospheric pressure and is therefore designedespecially for use with rotary seal assemblies or reactors to beoperated under vacuum. The circulation of cooling liquid to maintain thedesired temperature within chamber 33 will begin and continue in thisapparatus substantially as described above in reference to the otherdevices of this invention herein illustrated. A

Having thus described the present invention so thatl those skilled inthe art may be able to understand and practice the same, I state thatwhat I desire to secure by Letters Patent is defined in what is claimed.

What is claimed is:

1. Heat exchange apparatus which comprises a vessel to contain a fluidunder pressure and having an outlet port in its lower portion and inletport in the vessel above the outlet port, means comprisingtubes forseparately connecting the inlet and outlet ports to a liquid reservoirbelow the vessel, means for causing circulation ofliquid through saidvessel including means in said vessel between its inlet and outlet portsfor cooling said liquid, and means for increasing the pressure on liquidin the vessel.

2. Heat exchange apparatus which comprises a vessel to contain a uidunder l pressure and having an outlet port in its lower portion andinlet port in the i, vessel above the outlet port, means comprisingtubes for liquid, and means associated with said vessel for diminishingthe volume of said vessel and thereby increasing the pressure on liquidin the vessel.

3. Heat` exchange apparatus which comprises a vessel to contain a uidunder pressure and having an outlet port in its lower portion and inletport in the vessel above the outlet port, means comprising tubes forseparately connecting the inlet and outlet ports to a liquid reservoirbelow the vessel, means for causing circulation of liquid through saidvessel including means in said vessel between its inlet and outlet portsfor cooling said liquid, and means comprising a source of uid underpressure communicating with the interior of the vessel for increasingthe fluid pressure on liquid in said vessel.

4. Heat exchange apparatus which comprises a vessel to contain a Huidunder pressure and having an outlet port in its lower portion, astandpipe in the vessel and having an open ,end above the outlet port,means comprising tubes for separately connecting the standpipe and theoutlet port to a liquidreservoir below thevessel,v

means for causing circulation of liquid through said vessel including acoil in said vessel about said standpipe for conducting cooling fluidthrough liquid in the vessel, and means for introducing fluid underpressure into the vessel and thereby increasing the pressure on theliquid in the vessel.

5. The combination of elements set forth in claim 4 in which the meansfor introducing fluid under pressure Ainto the vessel include a tubeopening into the interior of said standpipe.

References Cited in the le of this patent UNITED STATES PATENTS StitzelAug. 4, 1885 Short Aug. 5, 1902 McClellan Oct. 10, 1916 Meyer Mar. 10,1931 La Bour Dec. 24, 1940 Fairlie et al. Nov. 11, 1941 Wincman Dec. 26,1944 Anderson Aug. 14, 1945 Roshong Dec. 16, 1947 Fausek May 24, 1949Voytech Feb. 17, 1953 Skillman Aug. 18, 1953 Weedman May 22, 1956Brumagim May 27, 1958 FOREIGN PATENTS Great Britain Apr. 24, 1930 GreatBritain July 10, 1945 Great Britain Apr. 25, 1951

